I still don't have a clue...
So far, that's about the only thing he's gotten right. I said I was done with the OP, not the thread. I still feel some affirmative obligation to try and keep a new guy (like Riley) from getting hurt or damaging a rifle due to following foolish advice from some self-styled expert.
A few things here; He's just provided an example of just such a misidentification with his coments about LC Match Ammo (he didn't say if this was M118, M852 or M118LR, but the 173 grain reference tips it as M118) being loaded with what he thought was IMR4320. It was most likely IMR4895 or possibly IMR4064. The 4895 load was the standard load for most of the Remington era at Lake City, as they were then tied in directly with DuPont, who at that time was still producing the IMR powders. LC Match ammo, however, would never have used the 4320, regardless of who held the contract. It is too slow-burning a powder and would produce excessive
port pressure, even if the ammo itself was well below the govt. specs for
chamber pressure. Despite the charge weight he describes, it was in all probablity IMR4895. Here's why. When a new run is begun at LC (i.e., a new batch of powder), the load is worked up from scratch, to the hundredth of a grain. Not a tenth, but one one-hundredth of a grain. The point isn't that the entire run will be loaded to that level of charge weight accuracy, but to establish (precisely!) where the center of a range of charge weights is to ensure that the outliers (both extreme high and low charge weights) still produce ammo that doesn't exceed the absolute max limit (as opposed to the average pressure) for that run. Yes, it's different for each lot of powder, and this is how that difference has to be accounted for. Smokeless propellants are an organic compound, composed of some materials over which we have little or no control of. If the material (cellulose, the basis for most smokeless propellants) falls too far outside what's usable, it doesn't get used. Aside from that, the powder makers can play with the blend a bit to get it to conform to certain burning characteristics that they desire. This, however, introduces certain variables, that simply can't be entirely eliminated. That's why powders vary from lot to lot. Within the "cannister grade" powders, this variation is held to specific levels in order for that powder to be labeled as a particular type or number of powder. This is what allows reloading books to have some degree of continuity between them, brand to brand. We've all seen the discrepencies between different reloading manuals in comparing loads, and seen how much difference there often is between charge weights. Part of this is due to their use of different lots of the "same" powder. I can pretty comfortably state that none of them is "wrong", but were "right" with the components they had on hand to do the load development. Still we see examples wherein one companies starting load is near, or in some cases exceeds anothers maximum load. Again, this is due in large part to powder variability from lot to lot. This is also why those of us who produce manuals are so adamant about starting low, and working up to the maximum loads shown with a good degree of caution. Lake City is currently loading the M118LR with RL-15, but the process of starting a new run with 1/100th of a grain accuracy is still followed, for each and every run. In my time with a previous employer, I certified literally millions of bullets for Lake City, using their components and their load specifications. I've mentioned this before, but that did not include a charge weight; it defined performance standards. Specifically, 2,580 fps @ 78 ft, and whatever powder charge of RL-15 I needed to use to attain that velocity, +/- a specified limit.
His assertion that cannister grade powders are being used by factories like Federal, Remington and Winchester is perfectly correct. But it's entirely incorrect to say that non-cannister grade or proprietary powders aren't being used as well. Or that proprietary powders are simply "defective" or out of spec runs that the ammo companies can get more cheaply than "good" stuff. That's ridiculous, and demonstrates a complete ignorance of the topic at hand. As I've already mentioned, most ammo makers will also have more than one powder that can be used for a given load. Availability issues plague ammo makers too, just like they do the average handloader. Except instead of not being able to get an 8 pounder from the local gunshop, they're dealing with not being able to get 2,000 lbs on schedule, for whatever reason. They need that flexibility, and alternate powders are the way that can be accomplished. No mystery here, nor is it some kind of conspiricy. It's just business.
He's also alluded to the notion that Lapua may be a bit different in how we develop our charges, but hasn't "verified" it with his own analysis. I'll save him the trouble; we use a variety of powders, not just Vihtavuori. And for exactly the same reasons as the others in the industry. That said, we, along with every other manufacturer, considers load data (both type and charge weight) to be proprietary information. Hopefully, with some of the information I've provided here, everybody will understand why this is a necessary position to take.
